System for maintaining the vacuum in a heating plant



- R. H. THOMAS SYSTEM FOR MAINTAINING THE VACUUM IN A HEATING PLANT Original Filed Dec. 10, 1921- 2 Sheets-Sheet 1 Feb. 7. 2 1,526,647

v R. H. THOMAS SYSTEM FOR MAINTAINING THE VACUUM m A mums mm Origin al Filed Dem l0, 1921 2 Sheets-Sheet z On I.auoanooouooneouaa noeanouncauoouncqoooaoaeon o cIFOO uoouoaocoooaeenuou ocoliatlnaccccanoooccc-o- Patented Feb. 17, 1925.

OFFICE.

RICHARD H. iiHOMAs, or-cnrcae innmors.

sYsTEMTon MAINTATNING THE vAcnUM INA HEATING- PLANT,.

Applicationfildflcmber 10,1921, Serial ivda 521,281. Renewed. 'J1ine 1c, 1924.

To all whom tt may concern:

Beiflk'now'n that I; RIoHAnn H; THoMAs; a' citizen of the United 7 States, and aresident er the'city ofGhicago, in the county ofCook and State of Illinois, have invented certain newand useful lmprovementsin a System fonMaintaining the Vacuum in a Heating 5 Plants and I do" hereby declare that the followingis a fulh'cleai', and exact descriptioir of the same, reference being had to the accompanyingdrawings, and to the numerals of reference markedthereon, which form a part of this speci'fication.

This inve'iition relatesto' a system of heating bysteam inwhich' the steam-is maintained in the r'adiators at apressure below that 1 of the atmosphere.

"It is an objector tliis in'vention to remove from the system of piping=in-such a steam 2 heating plant any air that may leakinto it.

It is a further object ofthis invention to"-"control the air removing' means in acco'rcl'arice with the degree of vacuum pres entin the system of pipes.

It is aiurthe'r object of this invention to return by-'means ofa positivepump the water-which has condensed in the piping so that the water shall find its way-back to the boiler regularly.

It is a. further-object of this system to separate the air which may be present in the/system of pipes from the water which has condensed therein and return the water to the boiler but the air to the atmosphere.

is a' further object of this invention to provide against flooding when the automatic control of'thepump by the vacuum is interrupted.

It "is a further object of this invention pump by the'level of the water due to condensation" when the continuous maintenance of the vacuum is not desired.

Other and further important objects of this invention will be apparent from the disclosures in the drawings and the following specification. The invention (in a preferred form) is illustrated in the drawings and hereinafter more fully described. On the drawings:

Figure 1 "is a front View of the appa= ratus.

to provide means for the control of the "-'Fig IIIQQ"1S"L longitudinalisection on the line"22 ot Figure 3.

Figuret is an end view of theapparatus.

* Fignre L is a detail showing in section one of the valves' used.

Figure 5 is a detail partly: in section showing the screen \used for straining the return from the pipe system.

* Figure 6 is a detailshowing a section through another of 'said valves.

r Figure 7 is a detail showing an electric switch employed inthis system.

As shown on the drawings:

Areturn from the system of piping is introduced by aunain 1 into the interior of a tank 2. This tank is of a general rectangular shape but itsnpper side as shown at 3 is: concave upwards to afi'ord a seat fora' cylindricalftank 4E. here the main 1 enters the tank 2 it is surrounded by a cylindrical screen 5 which extends completely acro'ss the tank 2. At the otherlend ofthe" screen is a hand-hole covered in the usual' manner by abolted plate 6 and the plate is equipped witha blow-off tap 7 which may -be=used-when needed toclean out the screen. Also when necessary the cover 6 maybe removed and the hand or a tool introduced through the :opening to clean out the screen.

Starting near the bottom of the tank 2 and=extending upward int-o the tank 41 is a pipe8'which at 9 is joinedto the suction end of: a jet pump oraspirator 10 which delivers toward the right in Figure 2. The jet pump is worked by a stream which is introduced through apipe 11, which as is most clearly seen in; Figure 3, is one of the delivery pipes of a centrifugal pump 12. There are two delivery pipes joined by a Y 13 to the delivery mouth 14 of the pump 12. V The suctionside of thepump 12 is connected by a'pi'pe 15 to a point near the bottom of thetalnk i as shown at 16 in Figures 1 and 2.

The other delivery-pipe 17 of the pump 12 goes from: the Y 13 to a valve 18 locatedat the top of the tank 4. \Vhen the valve 18 open connection is-established to the-boiler through the pipe 19, as indicated inlFigur-e 3.

The centrifugal pump 12 is driven by a motor 20 by means of the usual shafts 21 and 22 and the flexible connection 23. The motor is controlled by means of apparatus in a controlling box 25 which acts through conductors enclosed in the conduit 26 and going to the starting box 27 of the motor. The apparatus in the control box '25 is responsive to air pressure and is connected by means of a tube 28 with the upper part of the tank 2. A switch 40 is provided by which, when desired, the control of the motor 20 by the apparatus in the box 25 is removed and .the motor except under the circumstances pointed out below will remainidle. .111 the tank 4 is a float 30 which controls a lever 41, pivoted at 31. A connecting rod 7 32 goes from this lever'to the valve 18 andas will be seen from Figure 4, when the float 30 is low so that the connecting rod 32 is'high, the valve is in a position to close the pipe 17, but when the float rises the valve by descending opens a communication between pipes 17 and 19.-

A second connecting rod 33'is pivoted to the lever 41 on the other side of its fulcrum 31. This connecting rod operates a valve 34 illustrated in Figure 6. When the float is high the valve is high and closes the outletfrom the tank 4 to the atmosphere,

but when the float is low the valve being in the illustrated position affords communication between the interior of the tank 4 and the outside air.

From the valve 30 34 the rod 33 is continued and enters the box 42 illustrated .in Figure 7. This box is supported on the top of the tank 4 by standards 43 and it contains an electric switch 44 of any usual or desired kind, but preferably one of the snap type as indicated by the spring 45. The rod 33 is providedwithtwo stops 46 and 47 one of which 46 throws the switch into closed position when the rod 33 rises high enough and the other 47 throws the switch to open position when the rod 33 descends far enough. Preferably, there is considerable lost motion between the stop and the switch. l

A second circuit for operating themotor 20 is controlled by the switch 44 so that upon the rise of the float 30 high enough the motor is started.

The operation of the system is as follows:

The return main 1 from the system of piping brings into the tank 2 a mixture of air and water. If the pump 12 is running it establishes a jet through the jet pump 10 and consequently creates a suction through the pipe 8. If the returning water has filled the tank 2 above the level of the lower end of the pipe 8, this suction will cause water to be drawn upthat pipe. If the level of the water in tank 2 is below the mouth of pipe8 air will pass up this pipe in response to the atmosphere through 'valve 34.

The action of the centrifugal pump 12 in removing water from the tank 4 through the pipe 15 does not lower the level of the water in the tank 4 because an equal amount of water is delivered to the tank 4 through the pipe 11 and themouth of the jet pump 10. The water drawn up thepipe 8 and delivered through the aspirator 10 is in addition to the water flowing through the centrifugal pump 12. Thus, water gradually accumulates in the tank 4. Air does not accumulate however because whatever air is introduced through the pipe 8 passes check valve 50 prevents return of either air or water through the pipe 8.

; As the water accumulates in the tank 4, the float 30 rises. As it rises, valve 18is opened and the valve 34 closed by'the movement of the lever 41. When this change in the condition of the valves takes place the centrifugal pump which withdraws water from the tank 4 delivers it not through the pipe 11 as before but through the pipe 17. This is not only because the pipe 17 is now open but also because the closure of the valve 34 by preventing exit of air from thetank 4 adds to the resistance against flowthrough pipe '11. Consequently the centrifugal pump 12 will now withdraw more water from the tank 4 than it returns to it. The level of the water in the tank 4 will therefore be lowered and the float'30 will descend, closing the valve 32 and opening the valve 34.

The apparatus will then operate in the way first described to continue to remove water, air or a mixture of water and air this way will maintain a vacuum in the 7 system of pipes. If the leakage into the system is so small that the removal of air through the pipe 8 creates. a vacuum in the system, the pressure in the tank 2 will be lowered. Consequently, because of the connection 28 pressure in the box 25 will be lowered and the control devices therein will act to stop the motor 20.

Any leakage into: the systemof pipes will tend to create a rise in pressure in the tank 2 and therefore in the box 25. lVhen this rise is sufficient to operate the control de-v vices in the box 25 the motor 20 will again be started, the centrifugal pump 12 will therefore again work, and the apparatus 7 will withdraw air and water from the tank 2 as explained, the water being returned Me ea? to; the system bygoingthrough the boiler, but the-air beingu returned to the atmosphere through the opening 34. Consequently the pressure inthe system. of pipes will again be lowered until it reaches the desired degree of vacuum, when the controlling devices in the box 25 will again stop the motor.

When it is desired to avoid the expense of frequent operation of the motor 20, for example at night when the heatingplant does not need to maintainas high a temperature, or as in-mild "weather-when the interference of leakage with rapid circulation of steam is relatively unimportant, the switch 40 is moved to the position which will cause the apparatus in the box 25 to fail to start the motor. The water returning through the main 1 will then gradually fill the tank 2 until the trapped air makes it easier for the water to pass up the pipe 8. This will continue until the Water has risen in the tank 4 far enough to lift the float 30 and so the rod 33 so high that the switch 44 is thrown. This will start the motor 20 and the pump 12 will then withdraw water through pipe 15 and deliver it through pipe 17 to the pipe 19 and so to the boiler. The level of the water in tank 4 is thus lowered until the descent of float 30 and so of rod 33 causes the switch 44 to be thrown in the opposite direction. If, after this, the water continues to accumulate the process is repeated.

I am aware that various details of construction may bevaried through a wide range without departing from the spirit of this invention, and I therefore do not purpose limiting the patent granted otherwise than necessitated by the prior art.

I claim as my invention:

1.. In a heating plant, a boiler, a piping system, a tank, a connection from the return of said system to said tank, a second tank, a power driven pump, a jet pump, and connections whereby said power driven pump receives water from said second tank and delivers it to said jet pump, whereby said jet pump delivers to said second named tank and whereby said jet ptunp receives the contents of the first named tank, a float control in said second named tank, a connection from said power driven pump to the boiler controlled by said float control, and a connection from the upper part of said second named tank to the atmosphere also controlled by said float control.

In a heating plant, a boiler, a piping system, a tank, a connection from the return of said system to said tank, a second tank, a power driven pump, a jet pump, and connections whereby said power driven pump receives water from said second tank and delivers it to said jet pump, whereby said jet pump delivers to said second named tank and whereby said jet pump receives the contents of the first named tank, a float control in said second named tank, a connection :t'romsaid power driven pump to the boiler controlled by said float control, and a connection from the upper part of said second named tank to the atmosphere also controlled by said float con trol, a motor for driving said power driven pump, a pressure responsive controlling device for starting and stopping said motor, andconnections from said first named tank to said controlling device, whereby said 1no tor will be started when the vacuum in said first named tank diminishes to a predetermined point and stopped when the vacuum in said tank reaches a predetermined point.

3. A device of the class described, two tanks, a centrifugal pump receiving Water from one of said tanks and delivering it to the same, a float in said last named tank, means controlled by said float for causing the delivery of said centrifugal pump to be diverted from said tank, a pump control also operated by said float and means operated by the stream created by said centrifugal pump for moving the contents of the first tank into the second tank.

4. In a device of the class described, a tank, a jet pump in said tank below the usual level of water therein, a power pump and connections whereby said power pump operates said jet pump, an opening to the atmosphere at the upper side of said tank, and a float controlled valve for closing said opening when the level in said tank reaches a predetermined point.

5. A tank, a jet pump in said tank, a power driven pump for operating said jet pump, a float in said tank, two valves operated by said float, connections from said tank to the atmosphere controlled by one of said valves, a connection from the power driven pump to a point outside said tank controlled by the other of said valves, and means whereby upon the rise of the float in said tank one of said valves will be opened and the other closed.

6; In a device of the class described, a closed tank, a connection from said tank to a centrifugal pump, connection from the delivery side of said pump to said tank, a second connection from the delivery side of said pump to a point outside of said tank, a valve in said second connection, and means controlled by the level of liquid in said tank for closing said valve, a connection from said tank to the atmosphere, and means whereby when said last named valve is closed this connection will he opened and the reverse.

7. In a device of the class described, a boiler, a system of piping, a motor, a pump driven thereby, connections whereby said pump delivers water to the boiler and withdraws water and air from the system of piping, means governed by the degree of vacuum in the system for controlling the motor and means governed by the level of water for controlling the motor whenever the first. named means fails to maintain the water below a predetermined level.

8. In a device of the class described, a tank, a return pipe from a heating system connected therewith, a second tank, a connection from the second tank to the heating system a pump connected to said connection and to said second tank, and a second pump in the second tank operated by said first 15 mentioned pump andacting to draw liquid and gas from the first tank into the second tank.

In testimony whereof I have hereunto subscribed my name in the presence of two 2 subscribing witnesses.

RICHARD H. THOMAS. 

